Sustainability of compressed earth as a construction material

Abstract

Abstract Earth walls are considered to be sustainable materials for their low embodied energy. However, earth wall has to be protected from rain and dampness and meet up with contemporary aesthetic needs. Elevation of earth wall from the natural ground level, stabilisation of exposed earth walls and adequate overhang are construction and architectural design requirements for unbaked earth walls for protective purposes. Adequate stabilisation is cost intensive; so is adequate overhang in the context of modern architecture. In this chapter, sustainability challenges of compressed earth block are reviewed. The prospects of durability of cement stabilisation are considered. In an earlier research work, shelled compressed earth block (SCEB) evolved in an effort to meet the factor of adequacy of cement stabilisation for a durable earth wall with less cement. A case study of an industrial model of SCEB was made by evaluation compared with sand–cement block (SCB). The research outcome is sustainable shelled earth masonry unit with structural and aesthetic performance that are comparable to SCBs. Compressive strength of 3.65–4.46 MPa were recorded for SCEB as against 3.23 MPa of SCB. The initial rate of water absorption of SCEB was 3.2 kg/m 2 min against sand–cement 5.3 kg/m 2 min. Surface resistance results show that the percentage mass loss by abrasion of SCEB is 4.35%, which is much lower than that observed for SCBs (9.32%). Flexural strength of SCEB masonry panel was 1.07 N/mm 2 against the 0.71 N/mm 2 of sand–cement. The impressive performance of SCEB may well change the present state of non-utilization of earth construction in urban areas.